1. Field of the Invention
The invention relates to protecting device for an electrical circuit, more particularly to a non-light emitting protecting device for a string of series connected lamps.
2. Description of the Related Art
At present, a connecting device, such as an aluminum oxide wire, is connected in parallel to filaments of a string of series connected lamps for providing a conducting path when the filament of any one of the lamps breaks down. When some of the lamps in the lamp string break down, the load voltage of the other lamps, the current flowing therethrough, and the operating temperature will increase, thereby damaging more lamps and resulting in the risk of short circuiting. Also, a lot of time is needed to replace the damaged lamps.